Plas Newydd (meaning "new hall") may refer to several buildings and places in Wales:
Plas Newydd, Powys, a location in Carno community Plas Newydd (Anglesey), a historic house and garden on Anglesey Plas Newydd, Llangollen, a historic house and garden in Llangollen, Denbighshire Plas Newydd, Usk, a historic house in Usk, Monmouthshire
See also Plasnewydd, an electoral ward and former community in Cardiff, Wales